Fire crews are gaining on the Tenino complex of fires in south Thurston County, while a new threat emerged in Mason County on Tuesday, officials with the state Department of Natural Resources said.

The Haven Lake-area fire in north Mason County has grown to about 300 acres, and it has been joined by a smaller blaze called the Trask fire, DNR spokeswoman Janet Pearce said. The cause of the fires remains under investigation and no structures were threatened by the fires, she said.

Meanwhile, fire crews were getting the upper hand on the Tenino complex on Tuesday, said Jim Heuring, an agency representative with DNR.

The Kinsman Court fire was about 100 percent contained, he said, while the Johnson Creek fire was 50 percent to 60 percent contained. The Crane Street fire has a fire line around it and is in mop-up phase, Heuring said.

The cooler weather helped, he said, because even the small amount of rain that fell Tuesday morning raises humidity levels which can slow fire growth.

The Tenino complex remains under investigation, although the fires are thought to have been human-caused. Lightning has been ruled out, DNR officials have said.

The Teague Road fire, south of Rochester, also was 60 percent contained, according to DNR on social media. Heuring had no additional information about the fire.

Lightning has been ruled out as the cause of the Tenino complex, but there was still a chance of thunderstorms in Lewis, Thurston and Mason counties Tuesday evening, said Josh Smith with the National Weather Service. The chance of a thunderstorm going into Wednesday is not as high, he said.